Wheel well fairing for an aircraft

ABSTRACT

A wheel well fairing for reducing drag on an aircraft fuselage configured with an open wheel well for stowing landing gear of the aircraft. The wheel well fairing includes a Coanda fairing having a convex-shaped lower portion and an upper portion. The upper portion is configured for positioning adjacent an interior vertically-orientated sidewall of the wheel well, and the convex-shaped lower portion has a bottom surface configured to extend substantially parallel to and positioned adjacent with an outer hull surface of the fuselage. The convex-shaped lower portion is curved inwardly within the wheel well between the upper portion and bottom surface. The Coanda fairing is positioned at an aft portion of the wheel well to redirect airflow out of the wheel well in a rearward direction along the bottom hull surface of the fuselage.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application claims benefit under 35 U.S.C. § 371 tointernational application No. PCT/US2019/023332 filed on Mar. 21, 2019,which claims priority to U.S. provisional Application No. 62/647,242,filed Mar. 23, 2018, the contents of which are incorporated by referenceherein in their entireties.

FIELD OF INVENTION

The invention relates to an aircraft fairing, and more specifically to afairing mounted at a wheel well of an aircraft.

BACKGROUND OF INVENTION

Aircraft with retractable landing gear can have an open wheel wellconfiguration, as opposed to a wheel well with a moveable (openable andclosable) wheel well landing gear door, which is typically called a“pocket door.” The open wheel well design eliminates the weight andcomplexity of the wheel well door, at the expense of drag and noise. Thedrag and noise is caused by the wheel well ingesting and ejecting airflow in a disorganized fashion. Various aircraft manufacturers, such asthe Boeing model 737 aircraft and the Cessna Citation family aircraftare common examples of the open wheel well design practice.

The amount of recirculation, drag, and noise is typically proportionalto the volume of the wheel well not displaced by the landing gearassembly, Flexible gaskets or seals are often used to reduce the volumeopen to ingestion of air and recirculation. Even with the flexible sealsinstalled, open wheel wells must still be configured with significantclearance between the outer diameter of the tire and the inner diameterof the wheel well opening. For example, sufficient clearance must beprovided to allow a tire to be retracted into the wheel well withoutdamaging the surrounding structure. As such, the clearance from theopening also ingests, i.e., allows, air to enter at the forward portionof the wheel well and circulate in a chaotic manner in the large volumeor chamber that forms the wheel well. The ingested air is subsequentlyejected from the aft area of the wheel well and into the fuselagesurface air flow at a steep angle normal to the bottom surface of thefuselage. The mixing of the freestream flow outside of the wheel wellfrom the ejected flow can cause significant pressure drag and noise onthe aft surface of the wheel well.

The use of the Coanda effect to turn airflow has been in wide use formany years. It is the effect that allows a flow to follow a curvedsurface as on the flaps of an aircraft wing, as generally disclosed inU.S. Pat. No. 4,447,028 to Wang. A Coanda fairing using this effect ispositioned immediately downstream of an open wheel well.

Referring to FIG. 1, a bottom right side perspective view of a portionof an aircraft 100 (e.g., Boeing 737 model aircraft) having open rightand left wheel wells 110 with corresponding main landing gear and wheels112 retracted therein is illustratively shown. Each wheel well 110includes a flat wheel well fairing 114, as best seen in FIG. 2. In FIG.2, the prior art wheel well fairing 114 is formed by a plurality of flatL-shaped angle bracket segments 116A through 116E (individually orcollectively segments 116), each which are attached adjacently to a nextsegment end-to-end along an inner periphery of the wheel well 110 toform a semi-circular fairing shape, as illustratively shown in FIGS. 1and 2. Each segment 116 includes a horizontal leg 120, an upwardlydirected vertical leg 118, which together form the L-shaped bracket, anda flange or lip 122 extending upwardly from the horizontal leg portion120 opposite of and substantially parallel to the vertical leg 118, asillustratively shown in the various views of the first segment 116A andthird segment 116C in FIGS. 3A-4I. The horizontal leg 120 and lip 122form the aerodynamic features of the fairing 114. The vertical leg 118is provided for mounting the flange 114 to the inner wheel well, and hasno aerodynamic function.

The partial radius (i.e., cross-section) of the fairing segments 116 hasbeen limited in practice to ninety degrees or less. However, the lip 122of the flat wheel well fairing 114 acts as a restriction to the exitingair, and therefore does not significantly reduce the drag and noiseobserved at the open wheel well of an aircraft. More specifically, thelip 122 traps and diverts the aft exiting airflow to recirculate in theaft area of the wheel well, they causing pressure drag on the aft mostwall of the wheel well. This air then travels forward and is ejectedalong the back of the tire. In FIG. 1, arrow “A” illustrate ejected airflowing out of the wheel wells 110 which forms a vertical wall of airwhich has a high velocity and is directed substantially normal tofuselage 101. The ejected air initially flows downwardly and thenintermixes and collides with the surface air flow below the bottom hullof the aircraft, thereby causing air separation on the lower hull aft ofthe wheel well 110, which induces drag and noise aft of the wheel wells110.

In view of the aforementioned and other deficiencies in the prior art,it is desirable to provide an aft wheel well fairing that minimizesairflow separation, and thus reduces drag and noise observed both insideof and at an aft portion of an open wheel well of an aircraft.

SUMMARY OF THE INVENTION

The above disadvantages and deficiencies in the prior art are avoidedand/or solved by various embodiments of a Coanda shaped wheel wellfairing positioned at an aft portion of each wheel well of an aircraft.The wheel well fairing of the present invention redirects airflow out ofthe wheel well from a direction substantially normal to the bottomsurface of the fuselage, to a direction substantially parallel to thebottom surface of the fuselage, thereby reducing air separation and theundesirable drag and noise byproducts caused by the air separation.

In one embodiment, a wheel well fairing is provided for reducing drag onan aircraft having a fuselage configured with an open wheel well forstowing landing gear of the aircraft, the wheel well fairing comprisinga Coanda fairing having a convex-shaped lower portion and an upperportion, the upper portion being configured for positioning adjacent aninterior vertically-orientated sidewall of the wheel well, theconvex-shaped lower portion having a bottom surface configured to extendsubstantially parallel to and positioned adjacent with an outer hullsurface of the fuselage.

In one aspect, the convex-shaped lower portion is curved radiallyinwardly within the wheel well between the upper portion and bottomsurface.

In another aspect, the convex-shaped lower portion extends about an aftportion of the wheel well. The convex-shaped lower portion circumscribesat least ninety degrees along the aft portion of the wheel well.Alternatively, the convex-shaped lower portion circumscribes one-hundredand eighty degrees along the aft portion of the wheel well.

In still another aspect, the bottom surface of the convex-shaped lowerportion is configured with matching angles and contours as outer hullsurface of the fuselage.

In one aspect, the upper portion has a concave-shaped curvature andextends from the convex-shaped lower portion, and wherein theconcave-shaped upper portion is configured for positioning adjacent theinterior vertically-orientated sidewall of the wheel well. In anotheraspect, the concave-shaped upper portion has a radius less than a radiusof the convex-shaped lower portion.

In one aspect, the upper portion is linear-shaped and extends from theconvex-shaped lower portion, wherein the linear-shaped upper portion isconfigured for positioning adjacent the interior vertically-orientatedsidewall of the wheel well.

In one aspect, the wheel well fairing further comprises an angle bracketconfigured for mounting the wheel well fairing to the interiorvertically-orientated sidewall of the wheel well. The angle bracket canbe L-shaped or substantially L-shaped. In another aspect, the bottomsurface of the convex-shaped lower portion is attached to a horizontalleg of the angle bracket via at least one fastener. Moreover, the bottomsurface of the convex-shaped lower portion includes one of acounter-bore and countersink configured to receive a head portion of oneof the at least one fasteners. In another aspect, a vertical leg of theangle bracket is configured for attachment to the interiorvertically-orientated sidewall of the wheel well.

In one aspect, the upper portion is configured for mounting the wheelwell fairing to the interior vertically-orientated sidewall of the wheelwell.

In one aspect, the wheel well fairing is configured for installation onan open wheel well of one of a BOEING model 737 NG-700, 737 NG-800 and737 NG-900 aircraft to reduce drag and noise by reducing airflowseparation aft of a wing to fuselage junction. In another aspect, thewheel well fairing is configured for installation on an open wheel wellof one of a BOEING model 737 MAX-7, 737 MAX-8, 737 MAX-9, and 737 MAX-10aircraft to reduce drag and noise by reducing airflow separation aft ofa wing to fuselage junction.

In one aspect, air expelled out of the aft portion of the wheel well isat a low pressure and high velocity and flows in a direction rearwardalong the outer hull surface of the fuselage. In another aspect, theupper portion is configured to direct air flow downwardly out of thewheel well, and the convex-shaped lower portion is configured to turnthe air flow approximately ninety degrees and along the outer hullsurface of the fuselage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a bottom, right side perspective view of an aircrafthaving its main (rear) landing gear and wheels retracted and stowedwithin corresponding open right and left wheel wells and illustrating aprior art wheel well fairing circumscribing a portion of each wheel;

FIG. 2 is a top perspective view of a prior art wheel well fairingformed by a plurality of angle bracket sections which are alignedserially to form a curved shape corresponding to an open wheel well ofan aircraft;

FIGS. 3A-3I depict various views of a first angle bracket section of theplurality of prior art angle bracket sections of FIG. 1 and respectivelyillustrating a top plan view, a front elevation view, a bottom view, aleft front top perspective view, right front top perspective view, aleft side elevation view, a right side elevation view, a left frontbottom perspective view, and right front bottom perspective view;

FIGS. 4A-4I depict various views of a third angle bracket section of theplurality of prior art angle bracket sections of FIG. 1 respectivelyillustrating a top plan view, a front elevation view, a bottom view, aleft front top perspective view, right front top perspective view, aleft side elevation view, a right side elevation view, a left frontbottom perspective view, and right front bottom perspective view;

FIG. 5 depicts a bottom, right side perspective view of an aircrafthaving its main landing gear and wheels retracted and stowed within theopen right and left wheel wells and illustrating a wheel well fairing ofthe present invention circumscribing an aft portion of each wheel well;

FIG. 6 is a bottom perspective view of a plurality of angle bracketsections of the wheel well fairing of FIG. 5 and illustratively shownbeing aligned serially to form a curved shape corresponding to an openwheel well of an aircraft;

FIG. 7 is a bottom perspective view of a plurality of Coanda fairingsections positioned over the angle bracket sections of FIG. 6 andillustratively being aligned serially to form the curved shapecorresponding the an open wheel well of the aircraft;

FIGS. 8A-8I depict various views of a first Coanda fairing section ofFIG. 6 arranged with a corresponding first angle bracket section of theplurality of angle bracket sections of FIG. 7, and respectivelyillustrating a top plan view, a front elevation view, a bottom view, aleft front top perspective view, right front top perspective view, aleft side elevation view, a right side elevation view, a left frontbottom perspective view, and a right front bottom perspective view;

FIGS. 9A-9I depict various views of a second Coanda fairing section ofFIG. 6 arranged with a corresponding second angle bracket section of theplurality of angle bracket sections of FIG. 7, and respectivelyillustrating a top plan view, a front elevation view, a bottom view, aleft front top perspective view, right front top perspective view, aleft side elevation view, a right side elevation view, a left frontbottom perspective view, and a right front bottom perspective view;

FIGS. 10A-10I depict various views of a third Coanda fairing section ofFIG. 6 arranged with a corresponding third angle bracket section of theplurality of angle bracket sections of FIG. 7, and respectivelyillustrating a top plan view, a front elevation view, a bottom view, aleft front top perspective view, right front top perspective view, aleft side elevation view, a right side elevation view, a left frontbottom perspective view, and a right front bottom perspective view;

FIGS. 11A-11I depict various views of a fourth Coanda fairing section ofFIG. 6 arranged with a corresponding fourth angle bracket section of theplurality of angle bracket sections of FIG. 7, and respectivelyillustrating a top plan view, a front elevation view, a bottom view, aleft front top perspective view, right front top perspective view, aleft side elevation view, a right side elevation view, a left frontbottom perspective view, and a right front bottom perspective view;

FIGS. 12A-12I depict various views of a fifth Coanda fairing section ofFIG. 6 arranged with a corresponding fifth angle bracket section of theplurality of angle bracket sections of FIG. 7, and respectivelyillustrating a top plan view, a front elevation view, a bottom view, aleft front top perspective view, right front top perspective view, aleft side elevation view, a right side elevation view, a left frontbottom perspective view, and a right front bottom perspective view;

FIG. 13 is a right side elevation view of an alternative embodiment ofthe wheel well fairing of the present invention;

FIG. 14 is a front elevation view of the right wheel well fairing ofFIGS. 6 and 7;

FIG. 15 is a bottom, front perspective view of the right wheel wellfairing of FIGS. 6 and 7;

FIG. 16 depicts a bottom view of the right wheel well of an aircrafthaving a wheel well fairing of the present invention installed along anaft portion of the wheel well;

FIG. 17 depicts a bottom aft perspective view of the right wheel well ofFIG. 16 depicting a second, third and fourth sections of the wheel wellfairing of the of the present invention installed along the aft portionof the wheel well;

FIG. 18 depicts a bottom, front perspective view of the right wheel wellof FIG. 16 illustrating the wheel well fairing of the present inventioninstalled along the aft portion of the wheel well;

FIG. 19 depicts a bottom aft view of the aircraft of FIG. 16illustrating a bottom perspective view of the wheel well fairingsections installed along the aft portion of the wheel well;

FIG. 20A (prior art) and FIG. 20B are graphical images of bottom viewsof an aircraft without and with the wheel well fairing of the presentinvention mounted at the aft portion of an open right wheel well of theaircraft, respectively, and comparatively displaying computersimulations of high and low velocity surface air flow and turbulenceabout the open right wheel well of the aircraft with and without the aftwheel well fairing installed thereon; and

FIG. 21A (prior art) and FIG. 21B are enlarged graphical images of FIGS.20A and 20B, respectively, and comparatively displaying computersimulations of high and low velocity surface air flow and turbulenceabout the open right wheel well of the aircraft with and without the aftwheel well fairing installed thereon.

To further facilitate an understanding of the invention, the samereference numerals have been used, when appropriate, to designate thesame or similar elements that are common to the figures. Further, unlessotherwise indicated, the features shown in the figures are not drawn toscale, but are shown for illustrative purposes only.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention is directed to a wheel well fairing which isinstalled about an aft portion of each main landing gear wheel well.Each wheel well fairing is configured and contoured to induce a Coandaeffect over an exterior surface of the wheel well fairing so as toredirect air flowing downwardly out of the wheel well, i.e., in adirection substantially normal to the fuselage, to a rearward directionwhich is substantially parallel to the outer hull surface of thefuselage. In this manner, the discharged air flow from the open wheelwells is turned rearwardly at the exterior surface of the fairing andintersects and mixes substantially parallel with the surface air flowingalong the bottom portion of the fuselage without inducing the separationof airflow as currently observed prior art wheel well fairings. Morespecifically, the wheel well fairings of the present invention redirectthe airflow out of the open wheel well to reduce the airflow separation,drag and noise commonly observed at the bottom portion of the fuselageimmediately aft of the open wheel wells for the landing gear of theaircraft.

Referring to FIG. 5, a bottom, right-side perspective view of anaircraft 100 having its main (rear) landing gear and wheels 112retracted and stowed within a pair of open, circular wheel wells 110.Each wheel well 110 includes a corresponding wheel well fairing 214 ofthe present invention. The wheel well fairing 214 circumscribes at leastan aft portion of the wheel well 110, and in FIG. 5, is illustrativelyshown circumscribing approximately one-half or approximately one-hundredand eighty (180) degrees along the aft portion of the wheel well 110,although such circumferential length, number of degrees and/orpercentage of the circumference of a wheel well 110 is not consideredlimiting. For example, each fairing 214 can circumscribe approximatelyninety (90) degrees (e.g., an aft quarter of the wheel wellcircumference) to nearly the entire wheel well circumference (360degrees), subject to exclusion of a portion 119 (FIG. 16) of the wheelwell 110 at which the landing gear 112 support structures (struts, shockabsorbers, wheels, brake systems etc.) extend from and retract into astowed position within the wheel well 110. The curvature of the exteriorsurface of the wheel well fairing 214 induces a Coanda effect toredirect the air being ejected downwardly and out of the wheel well 110,to flow along the curvature of the exterior surface of the wheel wellfairing 214 and thereby turn approximately ninety degrees in ahorizontal and rearwardly direction, as shown by arrow “B” in FIG. 5.Referring to FIG. 1 and comparing the prior art wheel well airflow shownby arrow A to the air flow illustratively shown by arrow B in FIG. 5, itcan be seen that the ejected air out of the wheel wells 110 having theCoanda fairing 214 of the present invention is redirected over theexterior surface of the fairing 214 so as to turn rearwardly andintermix and flow with the surface air much closer to the outer hull ofthe aircraft 100 than previously observed with the prior art wheel wellfairings 114. In fact, the Coanda fairing 214 causes the air flowing outof the wheel well 110 to be at a lower pressure and higher velocity ascompared to the prior art wheel well fairings 114, as discussed below ingreater detail with respect to FIGS. 20A-21B. As such, the Coandafairing 214 turns the air flow rearwardly and substantially parallel tofuselage 101 to smoothly intermix with the surface air flow along thebottom hull of the aircraft, thereby significantly reducing airseparation, drag and noise at the aft portion of the wheel well 110.

Referring now to FIGS. 6 and 7, the illustrative wheel well Coandafairing 214 is formed in sections, illustratively from five L-shapedangle brackets 216A-216E (collectively 216) and five correspondingCoanda fairing sections 320A-320E (collectively 320) that are positionedover the L-shaped angle brackets 216. The L-shaped angle bracketsections 216A-216E shown in FIG. 6 and the corresponding Coanda fairingsections 230A-230E shown in FIG. 7 are positioned serially, i.e., end-toend to form a wheel well Coanda fairing 214 which, when installed on theaircraft 100, would illustratively circumscribe approximatelyone-hundred and eighty (180) degrees about the aft portion of the wheelwell 110, as shown in FIG. 5. Although five fairing sections 216, 230are shown in the drawings to form the fairing 214, such quantity isdiscussed for illustrative purposes only and is not considered limiting.Preferably, the Coanda fairing 214 does not extend greater thanone-hundred and eighty degrees about the aft portion of the wheel well110.

The Coanda fairing 214 is preferably formed in sections to enablecustomization for attachment within the wheel well 110. That is, thefairing 214 may require custom fitting around various protuberances suchas, for example, hydraulic lines, power conduits, fasteners, and otherstructural projections that cannot be readily repositioned and whichcould interfere with installation of the fairing 214. Referring to FIGS.8A-12I, the individual sections of the L-shaped angle brackets 216 caninclude bends, bores, holes, cutouts and the like to accommodate suchstructural protuberances around the circumference of the wheel well 110.Alternatively, where there are only a few or no protuberances presentaround the circumference of the wheel well 110, fewer sections or asingle elongated fairing 214 can be fabricated and installed around thecircumference of at least the aft portion of the wheel well 110.

Referring again to FIG. 6, each L-shaped angle bracket section 216includes a vertical leg 218 and a horizontal leg 220. By comparison, theangle bracket sections 216 of the present invention do not include theupright lip portion 122 of the prior art angle bracket sections 116, asshown in the prior art fairing 114 of FIGS. 2 and 3. Each vertical leg218 includes a plurality of holes 224, which are preferably equallyspaced apart and used for attaching the fairing sections to the innersidewall 111 (FIG. 17) of the wheel well 110 via a fastener (e.g.,machine screw, rivet, bolt, and the like—not shown). The horizontal andvertical legs 218, 220 of each segment 216 can be customized to includebends, cutouts and other openings 226 to accommodate various mechanicalconsiderations such as hydraulic lines, and other structuralprotuberances around the wheel wells 110, as discussed above. Duringinstallation of the fairing 214, the vertical legs 218 of the anglebracket sections 216 are first attached to the sidewall 111 of the wheelwell 110 via the fasteners, and then the corresponding Coanda fairingsections 320 are attached to the mounted angle bracket sections 216, asdiscussed below in further detail with respect to FIGS. 10A-10I.

Referring again to FIGS. 6 and 7, the wheel well Coanda fairing 320 isfabricated with a smooth, curved exterior surface to help air flowsmoothly transition from the interior portion of the wheel well 110 tothe outer hull surface along the fuselage 101 of the aircraft aft of thewheel well. The Coanda fairing sections 320 and L-shaped angle bracketsections 216 can be fabricated from well-known materials such asfiberglass, carbon fiber, Kevlar, Vectran or other aerospace gradereinforcing fibers and plastics. The fairing assembly 214 can also befabricated from metals such as aluminum, steel, stainless steel,titanium, or other aerospace grade metals, or a combination of compositeand metal materials. Processes for fabricating the fairing assembly 214can include forming, molding, machining, additive manufacturing, orcombination of these practices. Once the fabrication process of thefairing assembly is completed, the fairing assembly 214 can be attachedas a kit to older aircraft, or incorporated in to the wheel well 110 asa part of a new aircraft design.

Referring to FIG. 8, various views of a first Coanda fairing section320A of FIG. 7 arranged with a corresponding first angle bracket section216A of the plurality of angle bracket sections of FIG. 6 are shown, andrespectively illustrate a) a top plan view, b) a front elevation view,c) a bottom view, d) a left front top perspective view, e) right fronttop perspective view, f) a left side elevation view, g) a right sideelevation view, h) a left front bottom perspective view, and i) a rightfront bottom perspective view. FIGS. 9-12 respectively illustrate thesame various views of the second through fifth Coanda fairing sections320B-E of FIG. 7 arranged with the second through fifth angle bracketsection 216B-E of the plurality of angle bracket sections of FIG. 6. Forsake of best understanding the orientation of the five illustrativewheel well fairing sections 214 when installed in the aft portions ofthe right main landing gear wheel wells 110 of an aircraft 100, thereader is directed to FIGS. 16-19 in which FIG. 16 depicts a bottom viewof each fairing section 214 installed in the aft portion of the rightwheel well 110; FIG. 17 depicts a front elevation view of the second,third and fourth wheel well fairing sections 214B-214D installed in theright wheel well 110; FIG. 18 depicts a bottom, front right sideperspective view of the wheel well fairing sections 214; and FIG. 19depicts a bottom, aft view of the aircraft 100 illustrating a bottom,front perspective view of the wheel well fairing sections 214.

Referring again to FIG. 8, the individual sections of the Coanda fairing320 can also include bends, bores or holes, cutouts 326 and the like ina similar manner as the L-shaped brackets 216 to accommodate variousprotuberances such as, for example, hydraulic lines, conduits,fasteners, and other projections positioned around the circumference ofthe wheel well 110.

Referring to FIGS. 9G, 10G and 11G, side elevation views or profiles ofthe Coanda fairing 320 and corresponding angle bracket 216 areillustratively shown. The Coanda fairing 320 has a generally G-clef or Scurvilinear shape curvature which, in one embodiment, is formed by alarger convex-shaped lower portion 332 and a smaller concave-shapedupper portion 334 as shown in FIG. 10G. In particular, the convex-shapedlower portion 332 is generally formed by a substantially semi-circularportion 336 (FIG. 10E) having a linear bottom portion 338 terminating ata first free end 339. The concave-shaped upper portion 334 is generallyformed by a curved surface 337 (FIG. 10F) having a circumferentiallength extending radially approximately ninety (90) degrees such that adistal free end 340 of the Coanda fairing 320 terminates in a directionsubstantially normal to the linear bottom portion 338, as illustrativelyshown in FIG. 10F.

Each Coanda fairing section 320 is attached to a corresponding one ofthe L-shaped angle sections 216 via a fastener 340 (FIG. 10C), such as amachine screw, rivet or other fastener. The Coanda fairing sections 320are preferably attached to the horizontal legs 220 of the angle bracketsections 216 after the angle bracket sections 216 are attached to theinner sidewall 111 of the wheel well 110, as discussed above. Morespecifically, the bottom portion 338 of the Coanda fairing 320 includesa plurality of holes 341 (FIG. 8H) which are aligned with acorresponding plurality of holes 241 (FIG. 6) in the horizontal legs 220of the angled bracket sections 216. The horizontal leg 220 of the anglebracket 216 is positioned over an interior surface of the linear bottomportion 338 such that the horizontal leg holes 241 are aligned with theCoanda fairing holes 341. The fasteners 340 are then threaded orotherwise inserted through or into the holes 341/241 to secure theCoanda fairing section 320 to the corresponding angle bracket section216. Preferably, a counter-bore or countersink (not shown) is formedabout each Coanda fairing hole 341 to receive the corresponding head ofthe fasteners 340 so that it does not protrude above the bottom surfaceof the Coanda fairing 320 and cause undesirable air flow disturbancesand drag.

Referring to FIG. 13, an alternative shape of the Coanda fairingsegments 320 is illustratively shown such as, e.g., the third Coandafairing section 216C. The Coanda fairing 320 includes the convex-shapedlower portion 332 with a substantially linear bottom portion 338, asdescribed above with respect to the embodiment of FIGS. 8-12. However,in this alternative embodiment, the upper portion 334 of the Coandafairing segment 320 is shaped substantially linear, as opposed to havinga substantially concave-shaped upper portion. The linear-shaped upperportion 334 also directs the flow of air out of the wheel well 110 andaround the exterior surface of the larger convex-shaped lower portion332 to turn and expel the airflow approximately ninety degreesrearwardly from the wheel well 110.

In another embodiment, the Coanda fairing segments 320 can be attachedto the interior sidewall 111 of the wheel well 110 directly at the upperportion 334 of the fairing segments 320. For example, referring to FIG.10I, a plurality of holes 346 can be formed along a length of the upperportion 334 of the Coanda fairing segments 320. The holes 346 can beprovided along the entire length of the upper portion 334 or in one ormore tabs 347 provided along a length of the upper portion 334 of theCoanda fairing segments 320. A person of ordinary skill in the art willappreciate that where the Coanda fairing segments 320 are substantiallyrigid, the implementation of the angle bracket 214 may be omitted forattachment to the sidewall 111 of the wheel well 110.

Referring now to FIGS. 16-19, the wheel well Coanda fairing sections 214are illustratively shown mounted to the right main landing gear wheelwells 110 by the L-shaped angle bracket 216 as discussed above. TheCoanda fairing 320 is mounted to the wheel well 110 such that the bottomportion 338 of the Coanda fairing 320 is substantially aligned and flushwith (i.e., at the same or substantially the same angle as) thesurrounding outer hull surface of the fuselage 101.

Referring to FIGS. 14 and 15, the opposing ends of the Coanda fairing230 are preferably bent over and curved differently than the G-clef orS-shaped portions of the fairing 214. For example, the left side section230A includes various bends and cutouts to accommodate the main landinggear and other structural protuberances within the wheel well 110, asdiscussed above. In addition, referring to FIG. 14, both end sections(e.g., sections 230A and 230E) are curved and sloped downwardly from theadjacent section towards the distal end of the corresponding L-shapedangle brackets 216E to direct the wheel well air flow at the endsections 230A, 230E towards the centrally located sections (e.g.,sections 230B-230D) and then rearwardly out of the wheel well 110. Forexample, referring to FIG. 19, the end Coanda fairing section 230E isillustratively shown with an inclined slope from its end towards theadjacent section 230D.

Referring now to FIGS. 16-19, the wheel well fairing 214 isillustratively shown mounted at an aft section of the right wheel well.A person of ordinary skill in the art will appreciate that the wheelwell fairing assembly 214 can be installed in the left wheel well and/orother aircraft wheel wells in a similar manner. In FIG. 16, the fairing214 is shown partially circumscribing a flexible gasket or seal 113which is attached above the L-shaped brackets 216 of the fairing 214.The flexible seal 113 circumscribes and preferably contacts a lowersurface of the stowed wheels of the landing gear to help reduce airflowinto the wheel wells 110. The flexible seal 113 is discussed for sake ofcompleteness to better understand the configuration of the wheel wells110 as shown in the drawings and does not form a part of the invention.

Referring now to FIGS. 20A-21B, representations of various views ofscreen shots of computer-simulated aircraft to illustrate comparativeeffects on airflow with and without the wheel well fairing 214 of thepresent invention mounted on the right side wheel well 110 of theaircraft 100 are illustratively shown. The forward flight axis of theaircraft 100 is towards the right in the figures. FIGS. 20A and 21A areright side prior art views of an unmodified airframe 100 without thewheel well fairing 214 of the present invention. FIGS. 20B and 21B areright side views of the same airframe 100 being modified with the wheelwell fairing 214 mounted on an aft portion of the wheel well 110 of theaircraft. The drawings were taken from color-coded computer simulationswhich were configured and performed by the inventors using computationalfluid dynamics (CFD) validated on the well-known NASA “Common ResourceModel” (CRM) from the 5th AIAA Drag Prediction Workshop, although suchsimulation program is not considered limiting. The simulations conductedwere from an industry standard model of a 767/777/A330/A350 classaircraft. The CRM is used throughout the industry in wind tunnel and CFDwork to develop an understanding of drag and how to predict it. Highsurface pressure areas are illustrated by darker shading, as compared tolow surface pressure areas which are illustrated by lighter shading atspecific areas of the aircraft.

Referring now to FIGS. 20A and 21A, the CFD plot illustratively depictsa BOEING 737 having an open wheel well 110 and shows separation of flowon the fuselage aft of the wheel well 110. In the figures, thesubstantially horizontally directed lines depicted over the wing 102,wheel well 110 and fuselage 101 of the aircraft 101, as shown by arrow“C”, represent air streamlines along the outer hull surface of theaircraft 100. As seen in the figures, the air flow illustrated by thestreamlines C forward of the wheel well 110 are substantially horizontaland, at the forward edge of the wheel well 110, the ejected air turnssharply upwardly into the wheel well 110. The turbulent air flow withinthe wheel well exits proximate the aft portion of the open wheel well110 at a high velocity, as shown by arrow “A” in FIGS. 20A and 21A, aswell as in FIG. 1. The airflow exits the aft portion of the wheel well110 substantially normal to the fuselage 101 and forms a vertically anddownwardly directed wall of air before subsequently turning rearwardly adistance from the outer surface of the hull.

Referring again to FIGS. 20A and 21A, the absence of the streamlines Cimmediately aft of the wheel well 110, as shown by arrow “D”,illustrates that the airflow out of the aft portion of the wheel well110 at arrow A forms an air blockade against the surface air flow alongthe exterior surface of the fuselage, and undesirably results in airseparation, drag and noise occurring aft of the wheel wells 110. By wayof comparison, referring to FIGS. 20B and 21B, the surface flowstreamlines C indicated by arrow “E” are present aft of the wheel well110 because the wheel well Coanda fairing 214 of the present inventionturns the air expelled out of aft portion of the open wheel well 110approximately ninety degrees along the exterior surface of the Coandafairing 214, and therefore much closer to the outer hull surface of theadjacent fuselage 101, as also illustrated by arrow B in FIG. 5. Morespecifically, the CFD plots of the same open wheel well 110 with theCoanda fairing 214 installed illustrates significantly more closer andorganized air flow along the exterior surface of the fuselage 101 aft ofthe wheel well 110. This is evidenced by the straighter and morecontinuous streamlines E aft of the wheel well 110, as compared to theCFD plots of FIGS. 20A and 21A. Accordingly, the wheel well fairing 214of the present invention changes the air flow out of aft portion of thewheel well from a high pressure and low velocity flow rate (arrow D inFIGS. 20A and 21A), to a low pressure and high velocity flow rate, asindicated by arrow “F” in FIGS. 20B and 21B. In addition, the lowpressure/high velocity environment induced by the wheel well fairing 214can advantageously provide additional thrust in the forward directioncoming out of the wheel well 110, as opposed to the drag that isnormally induced by the prior art fairings 114 installed in the openwheel wells 110 of current aircraft.

Although various embodiments of the wheel well fairing 214 have beenshown and described herein for mounting on the BOEING 737 modelairframes (e.g., 737 NG-700 and the 737 MAX-7 airframes), such fairingand airframe are described for illustrative purposes only, as a personof ordinary skill in the art will appreciate that the wheel well fairing214 of the present invention can be provided for any other aircrafthaving an open wheel well 110 configuration.

Advantageously, the present trailing wheel well fairing 214 can beimplemented after the fuselage designs have been frozen or are alreadyin production. For a newly designed aircraft, the fairing 214 can beiterative and be optimized with regard to the other components. A personof ordinary skill in the art will appreciate that other embodiments ofthe wheel well fairing assembly 214 can be formed and positioned in asimilar manner described above for various aircraft models and atdifferent locations on the fuselage.

While the foregoing is directed to embodiments of the present invention,other and further embodiments and advantages of the invention can beenvisioned by those of ordinary skill in the art based on thisdescription without departing from the basic scope of the invention,which is to be determined by the claims that follow.

What is claimed is:
 1. A wheel well fairing for reducing drag on an aircraft having a fuselage configured with an open wheel well for stowing landing gear of the aircraft, the wheel well fairing comprising a Coanda fairing having a convex-shaped lower portion and an upper portion, the upper portion being configured for positioning adjacent an interior vertically-orientated sidewall of the wheel well, the convex-shaped lower portion having a bottom surface configured to align and extend evenly with an adjacent outer hull surface of the fuselage.
 2. The wheel well fairing of claim 1, wherein the convex-shaped lower portion is curved radially inwardly within the wheel well between the upper portion and bottom surface.
 3. The wheel well fairing of claim 1, wherein the convex-shaped lower portion extends about an aft portion of the wheel well.
 4. The wheel well fairing of claim 3, wherein the convex-shaped lower portion circumscribes at least ninety degrees along the aft portion of the wheel well.
 5. The wheel well fairing of claim 3, wherein the convex-shaped lower portion circumscribes one-hundred and eighty degrees along the aft portion of the wheel well.
 6. The wheel well fairing of claim 1, wherein the bottom surface of the convex-shaped lower portion is configured with matching angles and contours as outer hull surface of the fuselage.
 7. The wheel well fairing of claim 1, wherein the upper portion has a concave-shaped curvature and extends from the convex-shaped lower portion, and wherein the concave-shaped upper portion is configured for positioning adjacent the interior vertically-orientated sidewall of the wheel well.
 8. The wheel well fairing of claim 7, wherein the concave-shaped upper portion has a radius less than a radius of the convex-shaped lower portion.
 9. The wheel well fairing of claim 1, wherein the upper portion is linear-shaped and extends from the convex-shaped lower portion, wherein the linear-shaped upper portion is configured for positioning adjacent the interior vertically orientated sidewall of the wheel well.
 10. The wheel well fairing of claim 1, further comprising an angle bracket configured for mounting the wheel well fairing to the interior vertically-orientated sidewall of the wheel well.
 11. The wheel well fairing of claim 10, wherein the angle bracket is L-shaped.
 12. The wheel well fairing of claim 10, wherein the bottom surface of the convex-shaped lower portion is attached to a horizontal leg of the angle bracket.
 13. The wheel well fairing of claim 12, wherein the bottom surface of the convex-shaped lower portion is attached to a horizontal leg of the angle bracket via at least one fastener and includes one of a counter-bore and countersink configured to receive a head portion of one of the at least one fasteners.
 14. The wheel well fairing of claim 10, wherein a vertical leg of the angle bracket is configured for attachment to the interior vertically-orientated sidewall of the wheel well.
 15. The wheel well fairing of claim 10, wherein the bottom surface of the convex-shaped lower portion is attached to a horizontal leg of the angle bracket after the angle bracket is installed in the wheel well.
 16. The wheel well fairing, of claim 1, wherein the upper portion is configured for mounting the wheel well fairing to the interior vertically-orientated sidewall of the wheel well.
 17. The wheel well fairing of claim 1, wherein the bottom portion of the convex-shaped lower portion of the Coanda fairing forms a portion of an outer exterior surface of the Coanda fairing, said outer exterior surface being configured to reduce drag and noise from the aircraft by reducing airflow separation aft of a wing-to-fuselage junction.
 18. The wheel well fairing of claim 1 which is configured for installation in the open wheel well of a commercial aircraft to reduce drag and noise by reducing airflow separation aft of a wing-to-fuselage junction.
 19. The wheel well fairing of claim 1, in which an exterior surface of the Coanda fairing is configured to expel air out of the aft portion of the wheel well at a low pressure and high velocity and flows in a direction rearward along the outer hull surface of the fuselage.
 20. The wheel well fairing of claim 1, wherein the upper portion is configured to direct air flow downwardly out of the wheel well, and the convex-shaped lower portion is configured to turn the air flow in proximity to and along the outer hull surface of the fuselage.
 21. The wheel well fairing of claim 1, wherein the bottom surface extends parallel to the adjacent outer hull surface of the fuselage.
 22. The wheel well fairing of claim 1, wherein the bottom surface of the Coanda fairing is planar in shape to conform to the adjacent outer hull surface of the fuselage.
 23. The wheel well fairing of claim 1 further including cutouts that are sized and dimensioned to accommodate non-fairing objects mounted in the open wheel well of the aircraft.
 24. The wheel well fairing of claim 1, wherein the Coanda fairing is formed by a plurality of concatenated segments mounted along the vertically-orientated sidewall of the wheel well.
 25. The wheel well fairing of claim 1, wherein the Coanda fairing is incorporated into the wheel well as part of a new aircraft design.
 26. The wheel well fairing of claim 1, wherein the Coanda fairing is formed as a kit for installation in the wheel well of the aircraft.
 27. A wheel well fairing for reducing drag on an aircraft having a fuselage configured with an open wheel well for stowing landing gear of the aircraft, the wheel well fairing comprising a Coanda fairing having a convex-shaped lower portion and an upper portion, the upper portion being configured for positioning adjacent an interior vertically-orientated sidewall of the wheel well, the convex-shaped lower portion having a bottom surface configured to extend parallel to and positioned adjacent to an outer hull surface of the fuselage. 